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Lecturer: Hongqiangli

Email:lihongqiang2009@yahoo.com.cn

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Lesson Seven

Refrigeration and Refrigerants

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Topics

Refrigeration theory and evaluate1

Air pollution by Refrigerants2

Compressors33

44 Text and key words learning

Usages and Expressions35

4Refrigeration and heat pump

High temperature

Low temperature

RefrigerationEnergy

TH

TL

QH

QL

High temperature

Low temperature

Heat pumpEnergy

TH

TL

QH

QL

Summer

indoor

outdoor

Winter

outdoor

indoor

Topic one: Refrigeration theory and evaluate

5vapor compression system

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Indoorheat exchanger

Compressor

Expansion valve

四通换向阀

Four-way Reversing Valve

Outdoorheat exchanger

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Entropy

Absolutetemperature

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2

3

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Theoretical Vapor Compression Refrigeration Cycle 1-2 The cold saturated vapor at state 1 is compressed isentropically to the high temperature in the cycle at state 2. 2-3 The cycle is completed by an isothermal and isobaric heat rejection or condensing process from state 2 to state 3. 3-4 Saturated liquid at state 3 expands isenthalpicaly to the low temperature

and pressure of the cycle at state 4. 4-1 Heat is added isothermally and isobarically by evaporating the liquid phase refrigerant from state 4 to state 1.

Enthalpy

Pressure

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4

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COP: Coefficient of Performance

EER: Energy Efficiency Ratio

HSPF: Heating Seasonal Performance Factor

SEER: Seasonal Energy Efficiency Ratio

Btu of heat produced

Btu worth of electricity usedCOP

Btu/hr of cooling

watts usedEER

Btu of heat produced over the heating season

watt-hours of electricity used over the heating seasonHSPF

seasonal Btu of cooling

seasonal watt-hours usedSEER

11absorption system

water lithium bromideammonia water

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Ozone Depletion !反应输入物反应产物 反应催化剂

Topic two: Air pollution by Refrigerants

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decreaseincrease temperature

increase

atmosphere

earth

Global Warming !

Greenhousegases

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Arctic sea ice

17Reciprocation Compressor

Topic three: Compressors

18Reciprocation Compressor

Topic three: Compressors

19Reciprocation Compressor

Topic three: Compressors

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Rotary Compressor

Topic three: Compressors

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Rotary Compressor

Topic three: Compressors

22Screw Compressor

Topic three: Compressors

23Screw Compressor

Topic three: Compressors

24Screw Compressor

Topic three: Compressors

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Centrifugal Compressor

Topic three: Compressors

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Centrifugal Compressor

Topic three: Compressors

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Centrifugal Compressor

Topic three: Compressors

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1. Refrigeration and Refrigeration Systems

definition & classification of Refrigeration Systems

2. Refrigerants, Cooling Mediums, and Absorbents

definition & standard refrigerant designations

3. Classification of Refrigerants

classification of refrigerants based on ozone depletion

4. Phase out of CFCs, BFCs, HCFCs, and Their Blends

history of the phase out some alternatives

Topic Four: Text learning and keywords

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refrigeration 制冷 refrigeration system 制冷系统refrigerant 制冷剂 cooling medium 冷却介质vapor compression system 蒸气压缩式系统absorption system 吸收式系统gas expansion system 气体膨胀式系统ozone depletion potential (ODP) 臭氧消耗潜能global warming potential (GWP) 全球变暖潜能absorbent 吸收剂 brine 盐水hydrocarbon 碳氢化合物 halocarbon 卤代烃phaseout 逐步停用或淘汰 alternative 替代物Hydrofluorocarbons (HFCs) 氢氟烃Hydrochlorofluorocarbons (HCFCs) 氢氯氟烃Chlorofluorocarbons(CFCs) 氯氟烃Bromofluorocarbons(BFCs) Halons 溴氟烃HC （ Hydrocarbon ） 碳氢 FC （ Fluorocarbon ）

氟烃azeotropic 共沸的nonazeotropic 非共沸的

Topic Five: Text learning and keywords

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1. Refrigeration is the cooling effect of the process of extracting heat from a lower temperature heat source, a substance or cooling medium, and transferring it to a higher temperature heat sink, probably atmospheric air and surface water, to maintain the temperature of the heat source below that of the surroundings.

2. A refrigeration system is a combination of components, equipment, and piping, connected in a sequential order to produce the refrigeration effect.

cooling effect: 冷却作用 heat source: 热源 heat sink: 热汇cooling medium: 冷却介质 surrounding: ( 周围 ) 环境

in a sequential order: 顺序的 refrigeration effect: 制冷效应

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3. The compressed refrigerant is condensed into liquid form by releasing the latent heat of condensation to the condenser water.

4. Liquid refrigerant is then throttled to a low-temperature vapor, producing the refrigeration effect during evaporation.

5. After liquid refrigerant produces refrigeration during evaporation at very low pressure, the vapor is absorbed by an aqueous absorbent.

latent heat: 潜热 sensible heat: 显热condenser water: 冷却水

aqueous: 水的 水成的 absorbent: 吸收剂 吸收的

throttle: 节流 节流阀 expansion valve: 膨胀阀

32capillary expansion valve

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6. The solution is heated by a direct-fired gas furnace or waste heat, and the refrigerant is again vaporized and then condensed into liquid form.

7. A refrigerant is a primary working fluid used to produce refrigeration in a refrigeration system.

8. All refrigerants extract heat at low temperature and low pressure during evaporation and reject heat at high temperature and pressure during condensation.

solution: 溶液 解答 direct-fired gas furnace : 直燃式燃气炉waste heat: 废热

primary working fluid: 初级工作流体

extract: 吸取 吸收 抽出 reject: 排放 拒绝

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9. In a large, centralized air-conditioning system, it is more economical to pump the cooling medium to the remote locations where cooling is required.

10. Chilled water and brine are cooling media.

11. They are often called secondary refrigerants to distinguish them from the primary refrigerants.

centralized air-conditioning system: 集中式空调系统 economical: 节约的 经济的 economic: 经济的 经济学的 有关经济的

chilled water: 冷冻水 brine: 盐水

secondary refrigerants: 二级制冷剂 primary refrigerant: 初级制冷剂

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12. The refrigerant vaporizes, and the solution is restored to its original concentration to absorb water vapor again.

14. To compare the relative ozone depletion of various refrigerants, an index called the ozone depletion potential (ODP) has been introduced.

restore: 恢复 concentration: 浓度

ozone depletion: 对臭氧层的消耗破坏ozone depletion potential (ODP) : 臭氧消耗潜能introduce: 引入

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18. An azeotropic is a mixture of multiple components of volatilities (refrigerants) that evaporate and condense as a single substance and do not change in volumetric composition or saturation temperature when they evaporate or condense at constant pressure.

20. Nonazeotropic, including near azeotropic, shows a change in composition due to the difference between liquid and vapor phases.

azeotropic: 共沸的 ( 制冷剂 ) volatility: 挥发性物质volumetric composition: 体积构成 saturation temperature: 饱和温度

zeotropic nonazeotropic: 非共沸的 ( 制冷剂 )

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21.The difference in dew point and bubble point during evaporation and condensation is called glide, expressed in ℉.

22. Near azeotropic has a smaller glide than zeotropic.

dew point: 露点（温度） bubble point : 泡点（温度）glide ：滑移（温度） ℉ : 华式温度 Fahrenheit Celsius

glide: 温度 (滑移 )

Tc = （ 5 / 9 ） × （ Tf - 32 ）

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数字的表示法

1 用阿拉伯数字

1.1 在句首

在句首一般使用英语单词

Two men pushed on the crank with equal forces.

数字后面没有名词时，常用阿拉伯数字

300 decreased by 100 is 200.

Topic Six: Usages and expressions about Numbers

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数字的表示法1 用阿拉伯数字 1.2 在句中 个位数常用英语单词，十位数以上常用阿拉伯数字； Matter exists in three states: solid, liquid and gas.

The corporation produces a range of 16 alloy steel grades.

一句话中出现一个以上的个位数字（包括一些十位数）时，都用阿拉伯数字表示，或都用英文单词表示； He used a crew of 3 carpenters, 1 plumber, 6 laborers, 1 foreman, and 1 timekeeper.

单位名词前的数字通常用阿拉伯数字表示。 The car gained a speed of 4 feet per second.

At a speed of 17,500 miles per hour, …

Topic Six: Usages and expressions about Numbers

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数字的表示法1 用阿拉伯数字 1.3 两数连用 分别用英文单词及阿拉伯数字写出，习惯上将词组或句子之首计数的数字用英文单词写出； three 15 W lamps two 4-ton trucks

Topic Six: Usages and expressions about Numbers

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